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Which is the most valuable gem by carat weight?

Typically, a gemstone is priced by carat weight. But the price varies greatly between gemstones. Beyond that, colour, clarity, cut, polish, size, demand, and treatments are among other facets that are taken into consideration when applying value to a gemstone. There are many gems that are more valuable than diamonds. Emeralds, sapphires, rubies and alexandrite, just to name a few. But the most valuable gem of all time is a type of diamond. Here, we take a look at the most valuable non-diamond gemstone, as well as the two types of diamonds that hold the records for most valuable gem by carat weight.



The most valuable gem that is not a diamond is one that many have never heard of. Painite is an interesting brick-coloured gemstone. It is the most valuable non-diamond gem priced at £41,000-£49,000 ($50,000-$60,000 US) per carat. It is a very rare, naturally hexagonal gemstone. From the first discovery in the 1950s to 2005, only 25 small painite crystals were known to exist. In fact, until 2004, only two had been cut into jewellery-grade gemstones. Recently, more have been found, but it is still extremely rare and valuable.


Red diamond

Diamonds come in many colours, with red being the rarest. Because of this, the red diamond is among the most expensive gems in the world, priced at £820,000 ($1,000,000 US) per carat. To this day, there are only 20-30 red diamonds known to exist. Red diamonds are unique among coloured diamonds because other colours in diamonds are usually effects of impurities. Red and pink diamonds are not coloured by impurities, but rather as a result of miniscule defects in the lattice structure. So, a red diamond is a complete, perfect diamond, whereas a blue diamond contains boron, an impurity.


Pink Star Diamond

The most expensive gemstone ever was a specific diamond. It is worth £1,400,000 ($1,400,000 US) per carat. This 59.6-carat pink diamond is known as the Pink Star Diamond. It sold at auction in 2013 for £68,000,000 ($83,000,000 US), the highest price ever paid for any gemstone. The Pink Star Diamond is also sometimes referred to as The Pink Dream. The Gemological Institute of America boasted the Pink Star was the largest and most flawless naturally coloured pink diamond it had ever graded. It broke the previous sale record of the Graff Pink Diamond by almost double the amount.

So, the most valuable gemstone in the world is a particular pink diamond. For overall most valuable, red diamonds are worth the most money by carat weight. For non-diamond gemstones, painite is the winner of the most valuable gemstone in the world.

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